This invention relates to internal combustion engines and, more particularly, to internal combustion engines in which a common cylinder and a common piston are shared between a pair of alternate combustion chambers. More specifically, this invention relates to an internal combustion engine of the four-stroke type with a reciprocating piston member which partitions a common cylinder to form two combustion chambers.
Internal combustion engines are widely used as power plants for many equipment and apparatuses such as automobiles, power generators, pumps, compressors, ships, tractors, machines, and aeroplanes. In order to supply adequate power, conventional internal combustion engines are generally formed by connecting a plurality of alternately combusting cylinders together. Bach cylinder of an internal combustion engine generally includes a hollow combustion chamber inside which there is disposed a linearly and reciprocally moveable piston member.
In general, the piston is driven towards the cylinder head, which is usually the ceiling of a cylinder, to compress the gaseous fuel mixture introduced into the cylinder during one part of the engine cycle. The subsequent timely combustion of the compressed fuel causes an explosion to drive the piston away from the cylinder head. This movement also drives the connecting power transmission mechanism to deliver the resulting mechanical power outside of the cylinder for the intended use.
In general, 1) fuel intake, 2) compression, 3) combustion and 4) exhaustion are the typical steps involved in a complete engine operation cycle of a conventional four-stroke internal combustion engine. Because an engine cylinder must withstand the enormous explosive force during the engine operating cycles, internal combustion engines are typically made of steel, wrought iron or other ferrous or non-ferrous metal alloys which are inherently heavy and bulky. Since a plurality of engine cylinders are usually connected together to provide sufficient power output as well as for smooth engine operation, the weight of engines becomes an important factor to negotiate if to improve the efficiency of an engine is to be improved. In general, engine designers endeavour to minimize the engine weight-to-power output ratio, or, alternatively, to maximise the power-to-weight ratio per combustion cylinder. Also, in a multi-cylinder engine, usually only one cylinder delivers power at a time which means that the instantaneous power generating engine must also drive the remaining non-power generating pistons and the connecting mechanism. Therefore, it will be beneficial if the connecting mechanism or parts between cylinders can be minimized for a given set of cylinders.
For example, U.S. Pat. No. 6,318,309 describes an internal combustion engine in which two pistons are reciprocatively disposed in each cylinder thereby forming combustion chambers at each end of the cylinder plus a third combustion chamber between the pistons. However, two sets of rather complicated piston connecting rods are required and a third piston is responsible for a specific combustion chamber area not served by the other pistons. U.S. Pat. No. 3,010,440 teaches another example of an internal combustion engine having more than one piston disposed in a single cylinder in which each piston covers its own combustion chamber which is not served by the other piston.
In a conventional four-stroke cycle internal combustion engine, the complete engine operating cycle of fuel intake, compression, combustion and exhaust requires two cycles of linearly reciprocal motion of the piston member. In other words, the piston member has to move up and down twice in order to complete a single engine cycle. Since the engine cycle involving fuel combustion is the only power generating cycle, the other piston cycle is non-power generating but power consuming, noting that the piston is usually always connected to an external load. Hence, it will be highly beneficial if there can be provided an improved internal combustion engine or engine topology which can overcome or at least mitigate the short-comings associated with the afore-said disadvantages of conventional internal combustion engine.
Hence, it is an object of the present invention to provide an improved internal combustion engine or engine topology which overcome or, at least, mitigate disadvantages associated with conventional internal combustion engines. More specifically, it is an object of the present invention to provide an improved internal combustion engine or engine topology which serves to improve engine performance by reducing the engine weight-to-power output ratio. It is also an object of the present invention to provide an internal combustion engine or engine topology in which the piston only needs to go through a single set of leniently reciprocal motion in order to complete the fuel intake, compression, explosion and exhaust cycles of an engine operation. As a minimum, it is at least an object of the present invention to provide the public with a choice of a novel internal combustion engine or engine topology to be described hereinafter.
In view of the afore-said objectives and according to the present invention, there is provided an internal combustion engine including at least one engine cylinder, said cylinder includes a cylinder cavity with first and second cylinder heads which are interconnected by a cylinder wall, said cylinder includes a piston member which is slidably movement within said cavity and between a first and a second extreme position intermediate between said first and second cylinder heads, said piston member partitions said cavity into a first and a second combustion chambers which are in alternate combustion when in normal engine operation.
Preferably, said engine further including a slidable diaphram member in each said combustion chamber, said diaphram member includes a spacer separating a cylinder head and the corresponding piston surface of a combustion chamber, whereby defining the minimum volume of said combustion chamber.
Preferably, said engine further including a slidable member disposed in each said combustion chambers and partitioning said combustion chamber in to a first compartment with one end being a cylinder head and a second compartment with one end being said piston, said first and second compartments are generally not mutually communicable except at a specific position of said diaphram member at which position combustible gas in said first compartment will be transferred to said second compartment during normal engine operations.
Preferably, during normal engine operations, combustion occurs in said second compartment of one combustion chamber, that is, in the enclosed space between said diaphram and said piston, such that, during combustion, said piston are driven away from said diaphram and pushed towards the other chamber to compress said other chamber.
Preferably, said engine further including means to drive said diaphram towards said piston to remove exhaust from said cylinder subsequent to each combustion involving the chamber comprising said diaphram.
Preferably, combustible gaseous fuel is introduced into said first compartment of said combustion chamber at the time when exhaust is being removed from said second compartment of said chamber.
Preferably, combustible fuel is introduced into said first compartment through a valve aperture, said aperture when aligned with a specific part on said diaphram forms a communication path between said first and second compartments, thereby allowing compressed gaseous fuel to be transferred from said first compartment into the adjacent second compartment.
Preferably, combustion in one combustion chamber forces said piston and the diaphram member of another chamber to move towards the cylinder head of that another chamber to compress the gaseous fuel in said first compartment of that other chamber during normal engine operation.
Preferably, said cylinder is characterised in that when a combustion chamber is maximally compressed, the other combustion chamber is fully relaxed and vice versa.
Preferably, said diaphram member includes a base and a wall surrounding said base, said wall being axially extending away from said base and said cylinder head adjacent said base such that the axial extension of said wall defines the minimum axial clearance of said combustion chamber comprising said diaphram.
Preferably, an aperture is formed on said surrounding wall, such that said aperture provides a communication path between the two sides of said diaphram within said chamber when said diaphram is moved to a specific, pre-determined position.
Preferably, said pre-determined location corresponds to the position when said volume of said chamber is at a minimum.
Preferably, said piston member includes a bifurcated pair of legs protruding out of said cylinder, said bifurcated legs being connected with a rotary member which converts the translational movements of said bifurcated legs into rotary movements of said rotary member.
Preferably, each said bifurcated legs includes ratchet teeth which are engageable with teeth on said rotary member, said teeth on said bifurcated legs being arranged so that said teeth on said bifurcated legs are in driving engagement with the teeth on said rotary wheel when said bifurcated legs move in a first direction and said teeth on said bifurcated legs and said rotary member are not in driving engagement when moving in a direction opposite to said first direction, said direction of movements of said bifurcated legs for driving engagement with the teeth on said rotary member being opposite for teeth disposal on the two legs forming the bifurcated legs.
According to a second aspect of the present invention, there is provided an internal combustion engine including at least an engine cylinder, said engine cylinder includes a hollow cylinder room enclosed by a cylinder wall and a first and a second cylinder heads at the ends of said cylinder room, said engine cylinder further includes a piston having a first and a second piston surfaces, said piston is disposed within said cylinder room and partitions said cylinder room into a first and a second combustion chambers, wherein said first combustion chamber is formed by co-operation of said first piston surface and said first cylinder head and said second combustion chamber is formed by co-operation of said second piston surface and said second cylinder head, said piston being movable between a first and a second piston positions between said cylinder heads, said first and second piston positions correspond respective to said first and second combustion chambers of their minimum chamber volumes, such that, during engine operations, a complete cycle of reciprocating movements of said piston from one starting position back to that starting position corresponds to a complete engine combustion cycle in both said first and second combustion chambers.